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OPAL_1997_I440721

Event Shapes at 161 GeV
Experiment: OPAL (LEP)
Inspire ID: 440721
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Z.Phys. C75 (1997) 193-207
Beams: e- e+
Beam energies: (80.5, 80.5) GeV
Run details:
  • e+e- to hadrons

Event shapes at 161 GeV. Only the evnet shapes are implemented, not the mean values, or the cone jet observables.

Source code: OPAL_1997_I440721.cc
  1// -*- C++ -*-
  2#include "Rivet/Analysis.hh"
  3#include "Rivet/Projections/Beam.hh"
  4#include "Rivet/Projections/FinalState.hh"
  5#include "Rivet/Projections/ChargedFinalState.hh"
  6#include "Rivet/Projections/Sphericity.hh"
  7#include "Rivet/Projections/Thrust.hh"
  8#include "Rivet/Projections/FastJets.hh"
  9#include "Rivet/Projections/ParisiTensor.hh"
 10#include "Rivet/Projections/Hemispheres.hh"
 11
 12namespace Rivet {
 13
 14
 15  /// @brief event shapes at 161
 16  class OPAL_1997_I440721 : public Analysis {
 17  public:
 18
 19    /// Constructor
 20    RIVET_DEFAULT_ANALYSIS_CTOR(OPAL_1997_I440721);
 21
 22
 23    /// @name Analysis methods
 24    //@{
 25
 26    /// Book histograms and initialise projections before the run
 27    void init() {
 28
 29      // Initialise and register projections
 30      // Projections
 31      declare(Beam(), "Beams");
 32      const FinalState fs;
 33      declare(fs, "FS");
 34      const ChargedFinalState cfs;
 35      declare(cfs, "CFS");
 36      declare(FastJets(fs, FastJets::DURHAM, 0.7), "DurhamJets");
 37      declare(Sphericity(fs), "Sphericity");
 38      declare(ParisiTensor(fs), "Parisi");
 39      const Thrust thrust(fs);
 40      declare(thrust, "Thrust");
 41      declare(Hemispheres(thrust), "Hemispheres");
 42
 43      // Book histograms
 44      book(_h_thrust    ,  3,1,1);
 45      book(_h_major     ,  4,1,1);
 46      book(_h_minor     ,  5,1,1);
 47      book(_h_aplanarity,  8,1,1);
 48      book(_h_oblateness,  6,1,1);
 49      book(_h_C         ,  9,1,1);
 50      book(_h_rhoH      , 10,1,1);
 51      book(_h_sphericity,  7,1,1);
 52      book(_h_totalB    , 11,1,1);
 53      book(_h_wideB     , 12,1,1);
 54      book(_h_y23       , 20,1,1);
 55      book(_h_mult      , 26,1,1);
 56      book(_h_pTin      , 21,1,1);
 57      book(_h_pTout     , 22,1,1);
 58      book(_h_y         , 23,1,1);
 59      book(_h_x         , 24,1,1);
 60      book(_h_xi        , 25,1,1);
 61      book(_sumW,"/TMP/sumW");
 62    }
 63
 64
 65    /// Perform the per-event analysis
 66    void analyze(const Event& event) {
 67      // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
 68      const FinalState& cfs = apply<FinalState>(event, "CFS");
 69      if (cfs.size() < 2) vetoEvent;
 70      _sumW->fill();
 71      
 72      // Get beams and average beam momentum
 73      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
 74      const double meanBeamMom = ( beams.first.p3().mod() +
 75                                   beams.second.p3().mod() ) / 2.0;
 76      
 77      // Thrust related
 78      const Thrust& thrust = apply<Thrust>(event, "Thrust");
 79      _h_thrust    ->fill(thrust.thrust()     );
 80      _h_major     ->fill(thrust.thrustMajor());
 81      _h_minor     ->fill(thrust.thrustMinor());
 82      _h_oblateness->fill(thrust.oblateness());
 83
 84      // Sphericity related
 85      const Sphericity& sphericity = apply<Sphericity>(event, "Sphericity");
 86      _h_sphericity->fill(sphericity.sphericity());
 87      _h_aplanarity->fill(sphericity.aplanarity());
 88      
 89      // C parameter
 90      const ParisiTensor& parisi = apply<ParisiTensor>(event, "Parisi");
 91      _h_C->fill(parisi.C());
 92
 93      // Hemispheres
 94      const Hemispheres& hemi = apply<Hemispheres>(event, "Hemispheres");
 95
 96      _h_rhoH  ->fill(hemi.scaledMhigh());
 97      _h_wideB ->fill(hemi.Bmax());
 98      _h_totalB->fill(hemi.Bsum());
 99      
100      // Jets
101      const FastJets& durjet = apply<FastJets>(event, "DurhamJets");
102      const double y23 = durjet.clusterSeq()->exclusive_ymerge_max(2);
103      _h_y23->fill(y23);
104
105      // charged particles
106      _h_mult->fill(cfs.particles().size());
107      for (const Particle& p : cfs.particles()) {
108        const Vector3 mom3  = p.p3();
109        const double energy = p.E();
110        const double pTinT  = dot(mom3, thrust.thrustMajorAxis());
111        const double pToutT = dot(mom3, thrust.thrustMinorAxis());
112      	_h_pTin ->fill(fabs(pTinT/GeV) );
113      	_h_pTout->fill(fabs(pToutT/GeV));
114        const double momT = dot(thrust.thrustAxis(), mom3);
115        const double rapidityT = 0.5 * std::log((energy + momT) / (energy - momT));
116      	_h_y->fill(fabs(rapidityT));
117        const double mom = mom3.mod();
118        const double scaledMom = mom/meanBeamMom;
119        const double logInvScaledMom = -std::log(scaledMom);
120        _h_xi->fill(logInvScaledMom);
121        _h_x ->fill(scaledMom      );
122      }
123    }
124
125
126    /// Normalise histograms etc., after the run
127    void finalize() {
128      scale(_h_thrust    ,1./ *_sumW);
129      scale(_h_major     ,1./ *_sumW);
130      scale(_h_minor     ,1./ *_sumW);
131      scale(_h_aplanarity,1./ *_sumW);
132      scale(_h_oblateness,1./ *_sumW);
133      scale(_h_C         ,1./ *_sumW);
134      scale(_h_rhoH      ,1./ *_sumW);
135      scale(_h_sphericity,1./ *_sumW);
136      scale(_h_totalB    ,1./ *_sumW);
137      scale(_h_wideB     ,1./ *_sumW);
138      scale(_h_y23       ,1./ *_sumW);
139      scale(_h_mult      ,200./ *_sumW);
140      scale(_h_pTin      ,1./ *_sumW);
141      scale(_h_pTout     ,1./ *_sumW);
142      scale(_h_y         ,1./ *_sumW);
143      scale(_h_x         ,1./ *_sumW);
144      scale(_h_xi        ,1./ *_sumW);
145      // mean multiplicity
146      double nch     = _h_mult->xMean();
147      double nch_err = _h_mult->xStdErr();
148      Scatter2DPtr m_ch;
149      book(m_ch,2,1,1);
150      m_ch->addPoint(sqrtS(),nch,0.5,nch_err);
151    }
152
153    //@}
154
155
156    /// @name Histograms
157    //@{
158    Histo1DPtr _h_thrust,_h_major,_h_minor,_h_aplanarity,_h_oblateness,_h_C,_h_rhoH,_h_sphericity;
159    Histo1DPtr _h_totalB,_h_wideB,_h_y23,_h_mult,_h_pTin,_h_pTout,_h_y,_h_x,_h_xi;
160    CounterPtr _sumW;
161    //@}
162
163
164  };
165
166
167  // The hook for the plugin system
168  RIVET_DECLARE_PLUGIN(OPAL_1997_I440721);
169
170
171}